Valve control mechanism for hydraulic presses



5 Sheets-Sheet l June 17, 1941. w. P. MUIR ET A1.

VALVE CONTROL MECHANISM VFOR HYDRAULIC PRESSES Filed Nov. 1s, 195B ATTORNEY June 17, 1941. w. P. AMUIR ETAL VALVE CONTROL MECHANISM FOR HYDRAULIC PRESSES Filed Nov. 1s, 195s 5 sheets-sheet 2 IN VEN TORS W.P.MU1R

J.H.MAUDE f lzmam/ AT TORNEY June 17, 1941. f w. P. MUIR ETAL 22464379 VALVE CONTROL MECHANISM FOR HYDRAULIC PRESSES Filed Nov. 18, 1958 5 sheets-smet 5 MWIIENTORS ATTORNEY June I7, l WLR MUER ET AL VALVE CONTROL MECHANISM FOR HYDRAULIC PRESSES F'ld Nov. 1B, 1,938 5 Sheets-Sheet 4 ELMWENTUH@ ATTORNEY mw n .Junelz 1941. RMUIR ETAL 2,246,319

VALVE CONTROL MECHANISM FOR HYDRAULIC PRESSES Filed Nov. 18, 1938 5 Sheets-Sheet 5 INVEN-rons WILLIMRMUIR J HPLHJWQUDE .ATTORNEY `June 17,1941

' UNITED STATES VALVE CONTROL MECHANISM FOR HYDRAULIC PRESSES William P. Muir, Montreal, Quebec, and John H. Maude, Verdun, Quebec, Canada, assig-nors to Domini Quebec, Canada on Engineering Works Limited, Lachine,

Application November 18, 1938, Serial No. 241,190 In Canada `ctoiier 20, 1938 16 Claims.

This invention relates to valve actuating mechanisin for controlling the working valve of a hydraulic press such, for example, as the press disclosed in the co-pending application of John H. Maude, 207,733.

led May.13, 1938, under Serial N0.

According to one feature of the invention the v gle being extended to shift the valve to its working stroke position and being collapsed to elect reversal of the valve to its return stroke position.

Another feature of the invention resides in the provision of trip means whereby the toggle is automatically collapsed to reverse the working valve when a predetermined pressure is established in the main press cylinder during the working stroke oi the main press ram.

n further feature of the invention residesin the provision of trip means whereby the toggle is automatically collapsed to effect e, return stroke oi" the working valve when the main press ram reaches a predetermined position on its powerI stroke.

.another feature of the invention resides in the provision of meansior timing the collapse of the toggle in response to establishment of a deilnite predetermined pressure in the main pressing cylinder, said timing means being adjustable to provide dwell periods oi varying length during which the work is pressed under iull press toni'ldge.

.a still further ieature of the invention resides in the provision of a manually operable inching lertended to effect a working stroke of the press.

Fig. 2 is a view similar to Tcig, 1 but showing the component parts in the position which they occupy when the toggle is collapsed to eilect a return stroke of the press.

Fig. 3 is a view similar to the preceding iigures lout showing the component parts in a different position kto which said parts are shifted when actuating the control valve from the position shown in Fig. 2` to the position shown in Fig. 1.

Fig. 4 is a view similar to Fig. `lvlcutl showing the interposition of a stop memberin `the path of the main operating lever to limit the travel oi the lever so that collapse of the toggle occurs as soon as the lever is released after being moved to a toggle extending position.

Fig, 5 is an enlarged front elevation of the valve actuating mechanism per se.

Fig. 6 is a vertical sectional view of the assemioly appearing in Fig. 5.

Fig. 'i is a detail view showing the assembly of component links of the valve actuating toggle.

Fig. B is a detail sectional view showing the mounting of the toggle triplever.

Fig, 9 is a detail sectional view showing part of the mechanism by which the main control valve is actuated to effect a slow or inching movement oi the press ram in either direction.

Fig. ll) is a sectional view taken substantially along the line lltill in Fig. 6.

Fig. 1l is a detail view showing the mounting oi the inching control lever which is actuated to eiect the aforesaid slow or inching travel oi' the pressing ram.

' Figs. 12 and i3 are detail views illustrating the mounting oi the displaceable stop which is interposed in the path of the main operating lever in `the particular manner illustrated in Fig. d.

Fig, it is a 'diagrammatic view showing cne method of incorporating the l.invention in the hydraulic circuit of a conventional press.

'Referring more-,particularly to the drawings, t designates a valve operating plunger working in along guide t at the top of a control box l. The

upper end oi the plunger is connected, by suitable coupling means t (Fig. 1), to the stem 9 of a valve it working in a main valve casing ii. 1n the present instance valve it represents and functions in substantially the same manner as the main control valve of the hydraulic press disclosed in the said io-pending application of John lil. li/iaude, died May i3, 193B, under Serial No. 207,733. Consequently, theV following reference to the manner in winchv said valve isjutilized to control dow oi duid to and from the pressing and push hack cylinders is deemed soient for presfrom said cylinder through une zi, ports n, i3

p and i5, and main exhaust line 22. In this position of valve ill a working stroke of the press ram D is eected by the pressure fluid supplied to the main pressing cylinder. I

When valve I is in the position shown in Figure 2, fluid pressure is pumped to the push back cylinder C of the hydraulic press through the supply line I9, ports I4, I2 and I1, and line 2|. At the same time fluid, previously supplied to the main pressing cylinder, is exhausted therefrom through line 20, upper part of valve casing II, and line 22. In this position of valve I0 a return stroke of the press ram is effected by the pressure fluid supplied to the push back cylinders.

The lower end of plunger 5 is connected, by toggle links 24 and 25, to a toggle arm 26 formed integral with the main operating lever 21. This lever is loosely mounted on a pivot shaft 28 contained in the lower portion of box 1 and is provided with a second arm 29 lying substantially at right angles tothe toggle arm 26. As shown more particularly in Figure 7, link 25 is provided with a shaped stop 30 which engages with link 24 to prevent further clockwise rotation of the latter about the connecting pin 3| when said links are disposed `in the positions shown in Fig. 1.

When the press is idlinglready for a power stroke the valve IU, plunger 5, toggle links 24 and 25, toggle arm 26, and lever 21 are positioned as shown in Fig. 2. In this position of the parts anti-clockwise movement of toggle arm 26 from the vertical position shown is prevented by engagement of lever 21 with the lower end of the lever .slot 6a provided in the control box 1.

To start the press on its power stroke the lever 21 is iirst raised to shift the toggle'arm and the toggle links to the position shown in Fig. 3. With the parts in this new position lever 21 is then swung downwardly to shift the arm 26 and the links 24 and 25 to the position shown in Fig. 1. During this last motion plunger 5 and valve I9 are moved upwardly since the two links 24 and 25 become rigid in theposition shown in Fig. 3 by reason of the fact that the shaped stop 36 on link 25 engages link 24 to prevent further clockwise rotation of link 24 with respect to link 25. Consequently, (considering links 24 and 25 as one rigid link in a toggle system having one end pivot at shaft 28 and the other end pivot at the pin 32 connecting plunger 5 with the upper end of link 24) it will be seen thatwhen toggle arm 26 reaches the vertical position shown in Fig. 1 the toggle system will be locked against collapse because the pin connection 33 between link 25 and toggle arm 26 will have passed beyond the centre line between shaft 28 and pin 32, it being remembered that lever 21 is held against further anti-clockwise movement by the lower end of the lever slot 6a and that stop 30 is holding link 24against further clockwise movement relative to link 25.

A trip lever 34 is loosely mounted on a pivot shaft 35 contained in the upper portion of box 1.. An arm 36 depending fromthe inner end of this lever terminates in a horizontal projec* tion 31 which bears against link 25 when the latter is positioned as shown in Fig. 1. The outer portion of lever 34 overlies a tappet 3B adjustably secured to the upper end ofa tappet rod 39 carried by a plunger 40. This plunger works in a cylinder 4I formed in the bottom ,wall of box 1 and is held down by the lower end of a spring 42 encircling the rod 39. The upper end of spring 42 bears against a spring seat member 43 which is thus held to thelower end of the tappet; rod guide sleeve 44. In addition to serving as a guide for rod 39 said sleeve 44 constitutes part of a micrometer screw adjusting device through the agency of which the tension of spring 42 may be closely regulated. In this connection it will be noted that sleeve 44 is threaded through a bushing 45 carried by the box 1 and may be screwed up and down in said bushing to regulate the tension of spring 42. The upper end of sleeve 44 carries a cap 46 which slides on the upper portion of bushing 45 so that the position of the low.

er edge of the cap in relation to vertically spaced graduation markings 41 (Fig. 6) indicates the tension of the spring for any adjustment of said sleeve.

A hollow stationary plunger 49 is slidably fitted in a bore 50 provided in the movable plunger 40, said bore extending upwardly from the lower end of plunger 40 and being closed at its upper extremity. 'I'he lower end of plunger 49 is'anchored in the enlarged upper end 5I of a vertical bore 52 extending upwardly from the inner end of a horizontal valve Lore 53, the restricted portion of bore 52 being in line with the central bore of plunger 49 and being of substantially the same diameter. A timing valve 54 is slidably mounted in bore 53 and serves to control the iiow of iluid from a fluid inlet 55 to the vertical bore 52. In this connection it will be noted that valve bore 53 is shaped to provide a restricted portion 53a lying between two enlarged portions affording iluid pressure chambers 53h and 53o. The inner end of valve 54 is a close sliding t in the restricted portion 53a of the valve bore and is provided withl a iine tapered groove 56 which gradually deepens and Awidens in the direction of chamber 53o which is located at the inner end of the valve bore in communication with the lower end of port 52. The groove 56 extends longitudinally of valve 54 and is of substantially the same length as the restricted portion 53a of the valve bore. This groove serves, in certain positions of the valve, as a connecting port through which fluid, supplied to chamber 53h through inlet 55, ilows to chamber 53C, and from thence through port 52 and hollow plunger 49 to the pressure face afforded by the upper end wall of the plunger bore 5I) formed in plunger 40. The rate of fluid ow between chambers 53h and 53e is determined by the area of that portion of groove 56 which is in communication with chamber 53b and this may be regulated'by axial adjustment of valve 54. In the present instance such adjustment is made possible by the screw threaded connection 58 provided between the outer portion of valve 54 and a packing gland 59 secured to the `:ontrol box 1 at the outer end of the valve bore 53. A cap member 60 is iixed to the outer ends of valve 54 and serves as an operating knob by which the valve is turned to effect the desired adjustment. 'I'he cap 60 fits over a tubular portion of the gland 59 so that the position of the inner edge of the cap with reference to suitable graduations 6I on the gland indicates the position of the valve.

When the component links 24 and 25 of the toggle system have been moved to and locked in the position shown in Fig. 1 the press ram will move downwardly on its power stroke. When the ram engages the work the uid pressure in the pressing cylinder will increase until a predetermined tonnage is reached. This fluid pres' sure is transmitted through pipe connections 62 (Fig. 6) to the timing valve inlet 55 and bleeds through groove 56 to pressure chamber 53e from whence it passes upwardly through the hollow plunger 49 and acts/against the movable trip plunger 40. The intensity of this pressure acting on plunger 48 is resisted by the control spring 42 so that upward movement of plunger 40 does not occur until the iiuid pressure acting thereon exceeds the pressure at which spring 42 has been set by the micrometer screw adjusting device associated with the tappet rod 39. When plunger 40 thus moves upwardly it acts, through tappet rod 39 and tappet 38 to swing trip lever 34 in an anti-clockwise direction so that the lever projection 31 presses toggle link 25 to the right thus collapsing the toggle and permitting the valve operating plunger to drop to the valve reversing position shown in Fig; 2. The period elapsed from the instant the press ram makes contact with the work on the power stroke until'the toggle is tripped by the trip plunger 40 and trip lever 34 is determined by the rate of iluid ow to the bore 58 of the trip plunger and this is regulated by the setting of the timing valve 54. It is thus possible to have a varying dwell under full press tonnage so as to suit different types of pressing operations.

The invention also contemplates the provision of means for operating the toggle collapsing trip lever 34 whenthe pressing ram reaches any pre` determined position of its power stroke. To this end the outer extremity of lever 34 is disposed directly above the upper end of atrip rod 84 sliding in a suitable bearing 85 mounted on a convenient portion of the press. The lower end of rod 84 is disposed above one end of an intermediately pivoted lever 85 which is supported in the horizontal position shown by a suitable/supporting element 86a. The remaining end of lever 36 is disposed in the path of travel of an actuating member 61 which is actuated by the pressing ram during the power stroke of the press. As here shown the actuating member 61 is adjustably secured to a bar 68 which travels downwardly with the pressingl ram during the power stroke of the press. The position of the actuating member on the bar 68 determines the time of contact between the actuating member and the lever 65.

When the mechanical triprodl 64 is in use the hydraulic trip plunger is put out ofV action by closing the valve 54, this rbeing accomplished of a hollow hub 85 yformed integral with the box byrmoving the valve inwardly to disrupt com- Y munication between the pressure chamber 53h and the groove 56.

The foregoing description deals with what may be termed the semi-automatic operation of the valve actuating mechanism. In this operation the power stroke of the press is initiated by manual operation of the toggle extending lever 21 while the return stroke is initiated by automatic operation of the toggle collapsing trip lever 34.

The invention also contemplates the provision of means for enabling the operator to control reversal of valve l0 independently of the automatically operated trip lever 34. Referring to Fig. 4, it will be noted that a stop pin 1li has been interposed in the path of travel of the arm 29 which is formed integral with the inner end of the lever 21. In this case the valve I8 is set for a power stroke of the press by shifting the toggle links 24 and 25 and the lever 21 from the position shown in Fig. 2 to the successive positions shownin Figs. 3 and 4. When the lever 21 reaches the position shown in Fig. 4 it is prevented from moving further in an anti-clockwise direction by the engagement obtaining between the stop pin 10 and the arm 29. In this position of. the parts the toggle is not locked against collapse since the pin connection 33 between toggle arm 28 and link 25 is located at the right of the centre line between shaft 28 and the pin connection 32 between the plunger 5 and the toggle link 24. Consequently, as soon as the lever 21 is released by the operator the toggle will collapse and permit the valve l0 to drop to the position shown in Fig. 3.

As shown in Figs. 5, 12. and 13, the stop pin 18 is slidably mounted in the bore 1l 'of a bearing member 12 carried by the control box cover 8a. A portion of the bore 1I is constricted to provide a shoulder 13 opposing a shoulderv 14 formed on the pin 18. A spring 15 is conned between these shoulders and normally urges the pin inwardly to the lever obstructing position shown in Fig. 4. The pin 10 is also provided with an operating knob 18 and a projection 11, the latter working in a guide slot 18 formed in =the ccnstricted portion of the bore 1l. During semi-automatic operation of the press the pin 18 is retracted to and secured in an inoperative position by pulling outwardly on the knob 16 until the projection 11 clears the outer end of the guide slot 18. The knob 1lil is then turned through 90 so that the projection 11 bears against the outer end of the bearing memlber 12 (Fig. 13)V and prevents the spring 15 from returning pin 'lil to its operative position.

Plonger 5 is provided with lrack teeth 80 meshing with a pinion 8| loosely mounted onl a shaft 82 contained in the upper portion of control box 1. This shaft carries a sleeve 83 and has one end rotatably mounted in a suitable bearing 84. Sleeve 83 is rotatably mounted in the bore 1. Sleeve 83 is formed with a reduced outer portion 86 aiording a shoulder 81 which bears against a latch plate 38 secured to the hub 85. The reduced portion of the sleeve lying outside the latch plate is secured to the shaft 82 and to the encircling hwb portion 89 of an inching control 'lever 9B by a fastening pin 9|. The lever 9i!4 carries a spring latch 92 adapted to be selec- `tively engaged in notches 88a and 88h formed in the latch plate 88.

Sleeve 83 is provided, at .its inner end, with a flat surface 93 and a jaw 94 the latter being adapted for engagement with asimilar jaw 95 formed on the pinion 8l. The flat surface 93 engages and is adapted t'o depress the head of a pin 96 which is arranged to slide in a vertical bore 91 and bears on the inner end of the trip lever 31.

Lever 98 serves as an inching control lever which is normally secured in position A (Fig. 6)

by engaging latch 92 in notch 88a of latch plate 88. In this position of the lever the jaw dog 94 on sleeve 83 and the jaw 95 on pinion 8| are separated so as not vto interfere with the previously described operation of the toggle mechanisrn.

When lever 93 is to be used for inching control purposes it is shifted from position A through positions B, C and D to position F. During movement of the lever from position A to position B the flat surface 93 of sleeve 83 depresses pin 96 which, in turn, acts against lever 34 to shift the lever projection 31 to a position preventing the toggle links from locking in any subsequent motion of the mechanism. Rotation of lever 98 from position B to position C engages the jaw 94 on sleeve 83 with the jaw 95 on pinion 8l. Consequently, during further anti-clockwise rotation of lever 90 from position C to position F the engagement obtaining between the jaws 94 and 95 rotates the pinion 8| to raise the plunger 5 so that the working valve I0 is disposed in its neutral or mid position by the time lever 90 reaches its position F. In this latter position of lever 90 the latch 92 is engaged in the notch 88D of latch plate`88. With lever 90 in position F a slow or inching motiton of the press ram in the direction of its power stroke may be obtained by moving the lever downwardly through an angle of 151/2" to position G. Likewise a slow or inching movement of the ram on its return stroke may be obtained by moving the lever 90 upwardly through an angle'of,151/2 from position F to position D.v f

Having thus described what is now Vconsidered to be the preferred embodiment of this invention, it will be understood that various modifications may be resorted to within the scope and spirit of the appended claims. It will also be understood that the invention, while especially adapted for controlling the main working valve of a hydraulic press, as described herein, may also be used iny other relations.

Having thus described our invention, claim is: l

1. Valve actuating mechanism of the character described comprising, in combination, a valve, a rack member connected to said valve, a pinion meshing with said rack member, a shaft on which said pinion is rotatably mounted, means for operating said pinion and rack member in response, to rotation of said shaft comprising a driving element fixed to rotate with said shaft 'and a driven element on the pinion adapted to be engaged by said driving element, a valve operating what we lever and toggle links connected between said lever and said rack member.

2. Valve actuating mechanism of the character described comprising a valve, a slidably mounted plunger having one end connected to said valve, a pivoted operating lever, a toggle connected between said lever and the opposite end of said plunger and adapted to be extended to move the plunger in one directior` when said lever is swung to a predetermined position, a pinion meshing with rack teeth carried by said plunger, a shaft on which said pinion is rotatably mounted, means for driving said pinion in response to rotation of saidshaft, said means comprising a. sleeve fixed to rotate with said shaft and provided with a jaw adapted to engage a coacting jaw carried by said pinion, trip means movable into engagement with one of the toggle links for collapsing said toggle while said lever is still in its toggle extending position, and means for operating said trip means to collapse said toggle at a predetermined instant following operation of the lever to its toggle extending position.

3. Valve actuating mechanism comprising, in combination, a valve, a valve operating lever, a self-locking toggle connected between the valve and the lever adapted to be moved to and locked in an extended condition when the lever is moved to the end of its travel in one direction and to retain its extended condition when the lever is released after being operated to its toggle extending position, means independent of said lever for engaging and collapsing said toggle following operation of the lever toits toggle extending position, and means for limiting the travel of the lever in a toggle extending direction when it is desired to prevent the toggle becoming locked in its extended position, said means serving to stop the lever when the toggle has been extended sufllciently to operate the valve but has not yet reached its self-locking position.

4. Valve actuating mechanism comprising, in combination, a valve, a valve operating lever, a toggle connected between the valve and the lever so that the toggle becomes self locked in an extended position when the lever is swung to the full limit of its travel in a toggle extending direction and means adapted to be interposed in the path of movement of said lever to prevent full travel thereof in said toggle extending direction, said means serving to arrest the lever after the toggle has been extended to a valve operating position but -before the toggle has reached its self locking position.

5. The combination with the working valve of a hydraulic press, of a manually operable valve operating lever, a valve operating toggle connected .between said valve and lever so that said toggle is moved to and becomes locked in an extended position when said lever is swung to the full limit of its travel in a toggle extending direction, means adapted to be interposed in the path of movement of said lever to prevent full travel thereof in said toggle extending direction, said means serving to arrest the lever after the toggle has been extended to a valve operating position but before the toggle has reached its fully extended self-locking position and toggle tripping means including a member adapted to be moved against one of the toggle links to collapse the toggle after the latter has been moved to and locked in its fully extended position by said lever.

6. The combination with the working valve of a hydraulic press of a valve operating toggle connected to said valve, said toggle being adapted to be extended to shift the valve to its power stroke position and to be collapsed to shift the valve to its return stroke position, means for collapsing and extending said toggle and means for operating said valve independently of said toggle to permit shifting of the valve to working positions intermediate the working positions to which the valve is operated .by said toggle, said last mentioned means having a lost motion drive connection with said valve so that it does not interfere with extension and collapse of said toggle.

'7. In a hydraulic press, a press cylinder, mechanism for controlling the main working valve comprising a collapsible toggle connected to said valve, manually operable means for extending the toggle to shift the valve to a working stroke position, said toggle being self-locking in its fully extended condition, means other than said rst mentioned means for engaging and collapsing said toggle to effect shifting of the valve from a working stroke to a return stroke position and means for automatically operating said second mentioned means in response to the establishment of a predetermined pressure in the pressing cylinder during a working stroke of the press.

8. In Aa hydraulic press, a press cylinder, a ram therein, mechanism for, controlling the main working valve comprising a collapsible toggle connected to said valve, means for extending the toggle to shift said valve to a working stroke position, said toggle being self-locking in its fully extended condition, means other than said first mentioned means for engaging and collapsing said toggle to effect shifting of the valve from a working stroke` to a return stroke position and means controlled by the movement of the press` stroke. l

9. In a hydraulic press, a press cylinder. mechanism for controlling the main working valve,

comprising a manually operable lever, a collapsible'i toggle connected between said valve and lever, said toggle being moved to and locked in an extended position .when the lever is swung to the full limit .of its travel in. atoggle extending direction, a toggle collapsing trip member and means functioning automatically to move said trip member into toggle collapsing' engagement with one of the links of the extendedtogsle in response to the development of a predetermined pressure in the pressing cylinder during a working stroke of the press.

10. `The constructionset forth in claim 9 in which the last mentioned means comprises an auxiliary cylinder connected to the pressing cylinder, a vpiston working in said auxiliary cylinder adapted to be moved in one direction in response to establishment. of a predetermined pressure in the pressing cylinder and means carried by said piston for moving said trip member toa toggle collapsing position when said piston is moved .as aforesaid in response to development of a predetermined pressure in the pressing cylinder. `f

ll. Valve actuating'mechanism' comprising, in combination, a valve, a slidably mounted rack member connected to said valve, a pinion meshing with said rack member, a pinion ldriving shaft. means providing a lost motion drive oonnection between said pinion and said 4driving shaft, a manually operable lever, a toggle oonnected between the rack member and the lever so that the toggle `becomes self-locking in an extended position when the lever is swung to the full limit of its travel in a toggle extending direction, such extension of the toggle serving to shift the rack member and the valve in one direction, a trip member movable into, toggle collapsing engagement with one of the toggle links to effect collapse of the toggle after the latter has been extended by operation' of said lever. stop means adapted to be removably interposed in the path of movement of said lever to prevent full travel thereof in said toggle extending direction, said stop means serving to arrest -the lever after the toggle has been partly extended to a valve shifting position but before the toggle has reachedits fully extended self-locking position.

12. Valve actuating mechanism of the character described comprising, in combination, a valve. a slidably mounted rack member connected to said valve, a pinion meshing with said rack member, a shaft-on which said pinion is rotatably mounted and lost motion means for operating said pinion and rack member in response to rotation of said shaft comprising a driving element fixed to rotate with said ment on the pinion adapted to be engaged by said driving element, a pivotally mounted valve operating lever. a toggle connected between said lever and said rack member, said toggle being extended to operate the rack .member and the valve in one direction when said 'lever is swung to a predetermined position and a `toggle trip member movable into toggle collapsing engagea the toggle and return of the valve member to its Vshaft and a driven elewhen saidl inching control former position after the lever isreleased following operation thereof in a toggle extending direction to the extent permitted by said stop member.

14. In'a hydraulic press, a press cylinder.-

shift the valve to a working stroke position. said toggle being self-locking inv its fully extended condition, means other than said first mentioned means for collapsing said toggle to effect shiftving of the valve from a working stroke to a return stroke position. an inching control mechanism. for operating said valve independently of said toggle to effect a slow or inching travel of the valve in either a power stroke or a return stroke, direction, said inching control mechanism having a lost motion drive .connection with said valve and means for preventing said toggle assuming. a fully extended self-locking position mechanism is in 15. In `a. hydraulic press, a press cylinder, mechanism for controlling the main working valve comprising a collapsible toggle connected to said valve, means for extending the toggle to shift said valve to a working stroke position, said toggle being self-locking. in its fully extended condition, a toggle collapsing trip member mov- "able into toggle collapsing engagement with one of the links of the extended toggle to initiate collapse of the toggle while said lever is still in its togglel extending position. fluid pressure responsive means for operating said trip member to collapse the togglein response to the establishment Iof a predetermined pressure in the pressing cylinder during a working stroke of the press. mechanical means for operating said trip member to`collapse the toggle when, the press rain has travelled to a predetermined point ot its power stroke and means for rendering, said fluid pressure responsive means inoperative when 'thefmeehanieal means for operating the toggle trip member is in use. f i

16. Valve actuating mechanism comprising, in combination, a valve, a collapsible toggle connected to said valve, means for extending the Wiggle to shift said valve to one working position, said toggle being self-locking in its fully extended condition and means for collapsing said toggle to eifect shifting of the valve to a different working position to that Afrom which the valve is shifted by the iextension o f said toggle, said last mentioned means comp, a togglel trip member movable intotoggle collapsing engage-v ment with one of the links of the extended togsie. a cylinder and piston device for operating said trip member and means for supplying pressure fluid to said cylinder and piston device including a dow regulating valve.

MUIR.

VWimmer P. JOHN n mons. 

